Automatically-flashing electric lamp.



Patented Nov. 22, 1910.

W. J. PHELPS, DEGD. .T. w. PHELPS, ADMINISTRATOR. AUTOMATICALLY FLASHING ELECTRIC LAMP. APPLICATION FILED JULY 1e, 190a. 976,287.

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N L. UL M WILLIAM J. PHELPS, OF DETROIT, MICHIGAN;

J'. WILEY PHELPS, ADMINISTRATOR OF SAID WILLIAM J. PHELPS, DECEASED, ASSIGNOR TO THE ELECTRO-AD COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

AUTOMATICALLY-FLASHING ELECTRIC LAMP.

Specification of Letters Patent.

Patented Nov. 22, 1910.,

Application filed July 16, 1903. Serial No. 165,729.

To all whom it may concern:

Be it known that I, WILLIAM J. PHELPS, a citizen of the United States, and a resident of Detroit, county of Wayne, and State of Michigan, have invented certain new and useful Improvements in Automatically- Flashing Electric Lamps or the Like, of

which the following is a full, clear, and

exact description. 1

The invention relates to automatically flashing electric lamps, and more particularly to electric lamps having two or more filaments. i

The improvement seeks to provide an elec tric lamp which may be used with an ordinary lamp-holder and which is provided with a thermostatic switch for modifying the current to the lamp filaments and thereby vary the light emitted.

In the drawings is shown a longitudinal section through an incandescent lamp to which the invention is applied.

the vacuum bulb 11.

The lamp comprises a metal screw-shell or cap 10 which forms one of the lamp terminals for the reception of current. 'Within the outer end of the shell 10 is mounted an ordinary exhausted glass'bulb 11, which is supported in place by the compositionfillin'g 12. A disk 13 of porcelain or like material is mounted upon the end of the screw-shell -1O and carries a central stud or'ri'vet 14 which forms the second terminal of the lamp for the reception of current.

The thermostatic switch preferably comprises bent composite bar. formed of separate. strips of metal 15 and 16 soldered together. The strips 15 and 16 are formed of metals having different coefficiency of expansion, such for example as brass and steel, so that, when heated, the ends of the thermostatic bar will spread.

One end 15 of the metal strip 15 is separated from the metal strip 16, extends downwardly through the compositionfilling 12 and is fixed, preferably by solder, to the screw-shell terminal 10. In this mannerthe thermostatic switch 15, 16 is supported or held in place within the base of the lamp and with the main portionthereof extending withinthe hollow glass neck or mount 17 of The end 16 of the metal strip 16 'which' projects outwardly within the base of the lamp, carries a bent spring contact 18 which is, however, insu lated therefrom, as indicated. The opposite joined end of the strips15 and 16 carries an adjustable screw contact 19 adapted to engage the spring contact 18.

Two or more filaments 20 and 21 are and 21 while leading-in wires 23 and 24 are connected respectively to the opposite ends of the high power filament 20 and the low power filament 21.

By arranging the V-shaped or bent thermostatic bar within the hollow neck 17 of the lamp, it is exposed to and operated by the heat developed by the filaments of the lamp. When the high power filament glows, sufiicient heat is developed to gradually expand the thermostatic bar 15, 16 until contact between screw 19 and spring strip 18 is broken; The thermostatic bar will then gradually cool until contact between these parts is again established. In this manner the circuit through the lamp is automatically and successively opened and closed between the contacts 18 and 19. Where two filaments are employed, as indicated in the drawing, the thermostat will be so constructed that it will be heated when the high power filament is lighted and will the low power filament alone glows.

In the position shown in the drawing,-

current will flow from lamp terminal 14 by the leading-in wire 23, through the high power filament 20 by leading-in wire 22, contacts 18 and 19 and through the metal body of the thermostatic bar to the other lamp terminal 10. In this position the high power filament will alone glow with full candle power, while the low power filament 21 is short circuited. The heat developed by thehigh power filament pand the thermostatic bar 15, 16 until concool when will grttdually extact 19 is Shifted out of engagement with suitable manner.

contact 18. Current will then flow from lamp terminal 14 by leading-in wire 23, through the high and low power filaments 20 and 21 in series, and by leading-in wire 24 to the other lamp terminal 10. The low power filament will then alone glow while the high power filament acts as a dark and dead resistance cuttin down the amount of current used. The t ermostatic bar then slowly cools until contact is again made between the screw 19 and the spring strip 18. In this manner a flash lamp is provided suitable for electric signs, advertisements and other purposes, which is automatically turned up and down, varying the amount of light emitted. Screw contact 19 may be properly adjusted by insertinga suitable tool-through an opening 25 in the screwshell 10. After adjustment this opening may be closed with a drop of solder if desired.

vThe leading-in wires 22, 23 and 24 may be insulated from the thermostat 15, 16 in any- Preferably however, the leading-in wires or the thermostat or both or all of them are covered with an insulating layer of lacquer or varnish or the leading-in .wires could, if desired, be covered with insulatin'g sleev es or jackets.

Numerous changes could be made 1n the construction and arrangement of the invention without departure from the-essentials thereof.

Having thus described my invention what I claim as new and desire to secure by Let: ters Patent is 1. An automatically flashing, electric incandescent; 1amp comprising an exhausting globe, a filament therein, a'cap mounted on said globe and'iprovided with terminals for the reception 0 current, and a thermostatic switch mounted within said ca and extending within the neck of sai globe, said switch being interposed between said terminals and said filament and exposedto and operated by the heat of said filament to modify the flow of current therethrough, whereby said filament is valternately heated and cooled, substantially as described.

2. An electric, incandescent lamp having two filaments of different candle power connected in series and athermostatic switch exposed to and operated by the heatof said,

filaments and arranged to automatically open and close the short circuit around the low power filament, substantially as described.

3. An electric incandescent lamp having two filaments of difierent candle power connected. in series and a thermostatic switch mounted within the neck of the lam exposed to and operated by the heat 0 said filaments 'and arranged to automatically open and close a short circuit around the low-power filament.

WILLIAM J. PHELPS. Witnesses:

FRED R. BABoooK, WILLI M E. PHELPsQ 

